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Cliona delitrix is one of the most abundant and destructive coral-excavating sponges on Caribbean reefs. However, basic aspects of its reproductive biology, which largely determine the species propagation potential, remain unknown. A 2-year study (October 2009 to September 2011) was conducted to determine the reproductive cycle and gametogenesis of a C. delitrix population located in a shallow reef in Florida, USA. Mesohyl tissue collected from randomly chosen and tagged sponge individuals was sampled one to several times a month, and analysed by light and transmission electron microscopy (TEM). Cliona delitrix is oviparous and gonochoric, except for a few simultaneous hermaphroditic individuals. The C. delitrix reproductive cycle in Florida is from April to December, and is triggered by an increase in seawater temperature to 258C. Oogenesis and spermatogenesis were asynchronous among individuals; with different cohorts of oocytes co-occurring in females, and spermatic cysts in males. Granulose cells acted as nurse cells, contributing to the growth and maturation of both female and male gametes. Spawning of gametes was not always synchronized with full moon phase. Unlike most other oviparous sponges, the reproductive cycle of C. delitrix is versatile and includes multiple spawning events during the summer of each year. This characteristic maximizes sponge propagation on coral reefs during the warmer months of the year, particularly when thermal stress induces coral mortality. This aspect, combined with its success on polluted areas, make C. delitrix a suitable bioindicator of coral reef health.
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Asynchronous reproduction and
multi-spawning in the coral-excavating
sponge Cliona delitrix
andia chaves-fonnegra
, manuel maldonado
, patricia blackwelder
and jose v. lopez
NOVA Southeastern University, Oceanographic Center, 8000 North Ocean Drive. Dania Beach, FL 33004, USA,
Department of
Aquatic Ecology, Center for Advanced Studies of Blanes (CEAB-CSIC), Acceso Cala St. Francesc 14, Blanes, 17300 Girona, Spain
Cliona delitrix is one of the most abundant and destructive coral-excavating sponges on Caribbean reefs. However, basic
aspects of its reproductive biology, which largely determine the species propagation potential, remain unknown. A 2-year
study (October 2009 to September 2011) was conducted to determine the reproductive cycle and gametogenesis of a C. delitrix
population located in a shallow reef in Florida, USA. Mesohyl tissue collected from randomly chosen and tagged sponge indi-
viduals was sampled one to several times a month, and analysed by light and transmission electron microscopy (TEM). Cliona
delitrix is oviparous and gonochoric, except for a few simultaneous hermaphroditic individuals. The C. delitrix reproductive
cycle in Florida is from April to December, and is triggered by an increase in seawater temperature to 258C. Oogenesis and
spermatogenesis were asynchronous among individuals; with different cohorts of oocytes co-occurring in females, and sperm-
atic cysts in males. Granulose cells acted as nurse cells, contributing to the growth and maturation of both female and male
gametes. Spawning of gametes was not always synchronized with full moon phase. Unlike most other oviparous sponges, the
reproductive cycle of C. delitrix is versatile and includes multiple spawning events during the summer of each year. This char-
acteristic maximizes sponge propagation on coral reefs during the warmer months of the year, particularly when thermal
stress induces coral mortality. This aspect, combined with its success on polluted areas, make C. delitrix a suitable bioindicator
of coral reef health.
Keywords: Reproductive biology, life cycle, gametogenesis, bioindicator, Florida, Caribbean Sea
Submitted 9 December 2014; accepted 14 April 2015
Excavating sponges are becoming more prevalent on coral
reefs (e.g. Holmes, 1997; Scho
¨nberg, 2001;Ru¨tzler, 2002;
Ward-Paige et al.,2005; Scho
¨nberg & Ortiz, 2008; Carballo
et al.,2013). They spread faster in warmer temperatures
´set al.,1984;Ru¨tzler, 2002; Weil, 2002; Carballo
et al.,2013), and increase their boring rates at lower pH
(Wisshak et al.,2012; Duckworth & Peterson, 2013; Fang
et al.,2013; Enochs et al.,2015); abilities that can make
them strong competitors during expected climate change
scenarios (Carballo et al.,2013; Fang et al.,2013; Wisshak
et al.,2014; Enochs et al.,2015). However, the reproductive
strategies and propagation mechanisms of most coral-
excavating sponges are unknown or vague (Gonza
et al.,2013). This is the case for Cliona delitrix Pang (1973)
(Hadromerida, Demospongiae), one of the most destructive
species to Caribbean coral reefs; it excavates 10 12 cm deep
cavities inside coral skeletons, or deeper (Pang, 1973;
Zilberberg et al.,2006; Chaves-Fonnegra & Zea, 2007), and
spreads laterally at mean rates of 1.5 cm y
(Figure 1),
eroding massive live corals (Pang, 1973;Ru¨tzler, 2002;
Chaves-Fonnegra & Zea, 2007,2011). Zilberberg et al.
(2006) and Chaves-Fonnegra et al. (2015) suggested C. delitrix
propagation is sexually through larvae, but its reproductive
cycle and larvae are unknown.
An evaluation of environmental conditions, favourable for
the propagation of excavating sponges, is required to under-
stand their present and possible future ecological impacts
under climate change. Therefore, a fundamental step is to
determine the reproductive biology of excavating sponges,
which except for a few cases, remains poorly understood to
date. The sexual reproductive cycle of Cliona and Pione exca-
vating sponges has been described in five species: Cliona c.f.
celata Grant (1826) and C. viridis Schmidt (1862) (Piscitelli
et al.,2011); Pione truitti Old (1941) (Pomponi & Meritt,
1990); C. tenuis Zea & Weil (2003) (Gonza
´lez-Rivero et al.,
2013) and C. Vermifera Hancock (1867) (Bautista-Guerrero
et al.,2014). Annual changes in temperature represent the
main environmental variable influencing their oogenesis and
Cliona and Pione species can be hermaphrodites or gono-
choric, and are mostly oviparous (Nassonov, 1883;Le
1956; Pomponi & Meritt, 1990; Maldonado & Riesgo, 2008;
Piscitelli et al.,2011). However, their oocytes can be fertilized
internally before expulsion into the water column, whereas
embryogenesis is external (Nassonov, 1883; Bautista-
Guerrero et al.,2014). Viviparity has only been reported in
temperate Cliona lobata Hancock (1849) (Topsent, 1900). In
Corresponding author:
A. Chaves-Fonnegra
Journal of the Marine Biological Association of the United Kingdom, page 1 of 14. #Marine Biological Association of the United Kingdom, 2015
general, for both oviparous and viviparous sponges late-stage
oocytes are surrounded by a layer of parent cells, also called
‘nurse cells or granular cells’ (Warburton, 1961; Maldonado,
2009; Maldonado & Riesgo, 2009; Piscitelli et al.,2011).
Eggs are released, and embryonic development leads to a free-
swimming larval stage (Maldonado & Bergquist, 2002;
Maldonado & Riesgo, 2009). Characterizing the spermatogen-
esis in oviparous sponges can be difficult because of its short
time span, lasting only days to weeks (Maldonado & Riesgo,
2008). Therefore, investigation of spermatogenesis in the
genus Cliona remains incomplete. Also, collecting fertilized
eggs and larvae remains difficult, contributing to the lack of
knowledge of embryonic development in oviparous Cliona.
The study of reproductive cycles and gametogenesis in
coral-excavating sponges will aid in the understanding of
how sponges disseminate and contribute to coral mortality
and bioerosion, how human activities and climate change
may impact coral reefs and the distribution of these sponges
(Ru¨tzler, 2002; Ward-Paige et al.,2005; Scho
¨nberg & Ortiz,
2008), and to improve monitoring efforts and coral restor-
ation initiatives (e.g. Lang, 2003; Gilliam, 2012). With these
potential outcomes in mind, this study aims to determine
the sexual reproductive cycle and gametogenesis in the
coral-excavating sponge C. delitrix. Two hypotheses were pro-
posed: (1) C. delitrix is an oviparous, hermaphroditic sponge
similar to most other members of the genus Cliona; (2) this
species has synchronous female and male gamete maturation
leading to a single spawning pulse over one year, similar to
most other members of the genus Cliona.
Study area and sampling
Over 2 years, a population of Cliona delitrix was sampled on
the inner reef of Broward County, Florida, USA
(2680831.8′′N8080547.64′′W) at a depth of 18 –22 m. For a
more detailed description of the area see Banks et al. (2008).
During scuba dives, a 3 cm diameter steel corer and a
hammer were used to extract sponge tissue samples (1 cm
thick) from coral skeletons. During the first year (October
2009 to September 2010), samples were collected both from
four tagged individuals once a month and from 5 10 ran-
domly located individuals once or twice a month, depending
on how intense reproductive activity was inferred in the pre-
ceding sampling. During the second year (October 2010 to
September 2011), 10 tagged individuals were sampled once a
month, except in May, June, August and September when
samples were collected two to four times. Additionally, we
randomly sampled 5 10 individuals from April to
September one to four times per month. Tagged and
un-tagged individuals were selected haphazardly. To evaluate
if environmental variables influenced sponge reproduction,
temperature was recorded during the 2 years, and every 2 h
from two HOBO temperature loggers placed on the reef at
25 m depth (2680852.32′′N8080545.48′′W) by the South
East Florida Coral Reef Monitoring Project (SECREMP)
(Gilliam, 2012). Also, data on moon phases were obtained
from the US Naval observatory for each year (http://aa.usno.
Histology and light microscopy
Immediately after collection, all sponge tissue samples were
transported in ambient seawater to the laboratory and fixed
for histology in Bouin’s fixative solution for 2 days. Samples
were then rinsed in distilled water twice for 15 min and dec-
alcified using a 10% solution of HCl/EDTA for 3 days (modi-
fied from Renegar et al.,2008). After decalcification, samples
were rinsed with three successive changes of distilled water
(20 min each) and placed separately in 50% ethanol inside
50 mL Falcon tubes for at least 1 h. To further dehydrate
tissue, samples were placed in 70% ethanol for 1 h, and then
desilicified in 4% hydrofluoric acid overnight at 48Cto
remove spicules. After approximately 24 h samples were
rinsed in 70% ethanol for 20 min, and then placed inside hist-
ology cassettes and rinsed twice in 95% ethanol for 15 min
each, and in two changes of 100% for 10 min. Fragments
inside cassettes were submerged in xylene for two changes
of 15 min each, and placed in two changes of paraffin in the
oven at 608C for 15 min each. Samples were then transferred
to fresh paraffin, using a Sakura Tissue-Tek embedding centre
at the Nova Southeastern University (NSU)-Oceanographic
Center Coral Histology Lab. The paraffin blocks were placed
on a cold plate (Tissue-Tek 4650) to remove moulds, and
kept in the refrigerator at 48C in fresh water until sectioning.
Sections 4 mm thick were obtained on a Leica RM2125 micro-
tome. Three sections per sample were made, each separated by
1000 mm, and each was placed on a different slide. All sections
were stained with Heidenhain’s, and some with haematoxylin-
eosin for comparison (staining procedures in Chaves-
Fonnegra, 2014). Although Heidenhain’s is a common stain
Fig. 1. Excavating sponge Cliona delitrix on coral Diploria labyrinthiformis in San Andre
´s Island, Colombia. Photographs were taken in 2004, and 7 years after,
in 2011. The coral (yellow) died, and the sponge (orange) grew on most of the coral colony. Photos courtesy of S. Zea.
2 andia chaves-fonnegra et al.
for corals it is less commonly used for sponges, but it provided
a good resolution of sponge structures such as cell nuclei (dark
red), collagen and choanocytes (blue) and granulose cells
To estimate gamete density over time, two photographs
(100×) of each of the three sections per individual were
taken. Photographs were taken at least 210 mm apart to
avoid overlapping areas and density overestimation. The
area of suitable tissue varied among sections due to the ‘por-
osity’ of the tissue and the holes left by the HCl-digested
coral calcium carbonate. Thus, to obtain equivalent areas of
tissue per picture, all pictures were contrasted on a white back-
ground using the program Corel Paintshop Pro X4, and a
Matlab code was written to calculate the percentage of tissue
(Chaves-Fonnegra, 2014).
Digital histological images were analysed to measure and
count gametes and to study cytology. To compare different
individuals, the number of reproductive structures of interest
(i.e. gametes) were assessed from an area of 1 mm
in each
photograph. Thus, the total tissue area microscopically
sampled for each individual was the sum of the area of the
six pictures taken (6 mm
). The number of oocytes per mm
(O) of tissue was estimated applying the formula proposed
by Elvin (1976) and used for sponge gametes estimations by
Maldonado & Riesgo (2009):
Where Ois the number of oocytes or spermatocytes per mm
of tissue, Nis the number of oocytes or spermatocytes counted
in the histological sections per individual (in this case 6 mm
tis the thickness of section (4 mm), dis the average diameter
of oocytes for each month and F(¼41.67) is the factor to
convert the volume of the observation to 1 mm
To describe the reproductive cycle and examine the poten-
tial relationship between gametogenesis and seawater tem-
perature, we plotted the monthly density and percentages of
oocyte and spermatocyte (number of structures mm
monthly average temperature. To calculate the diameter of
reproductive structures, pictures of up to 15 reproductive
structures (eggs, sperm or transdifferentiated choanocytes)
were taken in each individual, and measured using the
Image J program ( Also,
Pearson or Spearman correlations (depending on the
normal distribution of the values) were used to test if the
density of reproductive structures correlated with seawater
temperature. To avoid confusion in the text, oocyte develop-
ment is referred to as stages IIV, whereas spermatic cysts
development as cysts 1 4.
Electron microscopy
Subsamples from the sponges were fixed for transmission elec-
tron microscopy (TEM) in 2% glutaraldehyde and 0.05 M
sodium cacodylate buffer prepared in filtered seawater to
maintain osmolarity, following the protocol by Miller et al.
(2011). Only those samples corroborated by the light micros-
copy study to contain reproductive elements were further pro-
cessed for TEM. After the primary fixation, subsamples were
rinsed three times for 10 min each in 0.05 M sodium cacody-
late buffer. Then, they were transferred to a second fixative
solution of 1% osmium tetroxide in buffer for 45 min, fol-
lowed by three 10-min rinses in the 0.05 M sodium cacodylate
buffer. Samples were dehydrated in a graded series of ethanol
at 20, 40, 60, 70, 90 and 100%, three changes of 5 min each.
Following dehydration, samples were placed in Spurr resin,
which was changed three times over a period of 3 h. Samples
were then placed in flat embedding moulds and polymerized
overnight at 608C in a stable temperature oven. Blocks were
trimmed using GEM/STAR single edge razors to expose the
area of tissue of interest. Blocks were then sectioned to
90 nm in a Porter Blum MT-2 Ultramicrotome fitted with a
diamond knife. To obtain membrane contrast, sections were
placed on copper grids and stained with lead citrate (6 min)
and uranyl acetate (10 min). Sections stained with lead
citrate and/or uranyl acetate, and non-stained sections were
observed in a Philips 300 TEM at the NSU Oceanographic
Center, and electron micrographs taken with a JEOL JEM
1400 X at the Miller School of Medicine at the University of
Developing oocytes (stages I and II, Table 1,Figure 2) were
found in Cliona delitrix tissue in all sampled months for
both years, except April 2010 (Figure 3), but matured
(stages III and IV, Table 1,Figure 2) only within the period
from April May to November December, depending on
year (Figures 3 &4). When the smallest recognizable
oocytes appeared, choanocyte chambers around them were
absent or disorganized (Figure 2A). Granulose cells (nurse
cells) played an important role in the maturation of oocytes;
stage II and III oocytes form pseudopodia becoming amoeb-
oid in shape, engulfing granular cells, as observed in histology
and TEM micrographs (Figure 2C, D, G, H). At stage IV
granular cells abundantly surrounded oocytes (Figure 2E, F).
During the warmer months, different cohorts of oocytes
Table 1. Histological features of oogenesis stages in Cliona delitrix. Stage I: young oocytes during the first growth phase; Stage II: oocytes undergoing yolk
accumulation; Stage III: oocytes about to complete yolk accumulation; stage IV: mature oocytes.
Stage I Size: 10 45 mm (21.7 +7.3; N ¼170); shape rounded; no accumulation of yolk granules, or some of them start to be
Stage II Size: 11.2 79.9 mm (34.02 +10.6; N ¼1214); shape oval to amoeboid with pseudopodia; yolk granules, lipids and
inclusions with heterogeneous content are accumulated in the cytoplasm and granulose cells are in contact and being
engulfed by the oocyte
Stage III Size: 23.8 97.2 mm (56.4 +11.0; N ¼585); shape rounded, although still forming pseudopodia; yolk granules and
inclusions only in peripheral cytoplasm; many granulose cells surrounding or inside the oocyte
Stage IV Size: 52.596.3 mm (73.5 +8.1; N ¼117); shape completely round and surrounded with granular cells; space between the
mesohyl and the oocyte-granular cells is formed
reproduction in the sponge cliona delitrix 3
were observed to co-occur in the same female individual
(Figures 2F &5). These results suggested that the oogenesis
of C. delitrix was asynchronous at the individual level.
During summer time, oocytes can mature relatively rapidly,
varying between 2 weeks and a month (Figure 5, female 4).
However, a female individual did not necessarily produce
oocytes every month (Figure 5). Also, the same female indi-
vidual could produce gametes during most of the reproductive
cycle (April December), showing one or two peaks of higher
density, while a few females maintained oocytes all year round
(Figure 5). Neither embryos nor larvae were observed in any
Transdifferentiated choanocytes (i.e. the precursor sperm-
atogonial cells, Figure 6A, B) were found in most of the
sampled dates during the warmer months, but spermatic
cysts were detected only at some of the sampling dates during
Fig. 2. Oogenesis observed by light microscopy and TEM. (A) Young oocytes during the first growth phase in stage I; (B) Oocytes in stages II and III with
inclusions in the cytoplasm; (C) Oocyte in stage III with yolk only in the periphery; (D) Granulose cells inside stage III oocytes; (E) Oocyte stage IV separated
from the mesohyl and completely surrounded by granulose cells. (F and G) TEM of oocytes in stage II with granulose cells and inclusions in the cytoplasm.
Abbreviations, ch: choanocytes chambers; Gr: granulose cell; mi: mitochondria; N: nucleus; nu: nucleolus; O: oocyte.
4 andia chaves-fonnegra et al.
Fig. 3. Density of reproductive structures in relation to seawater temperature. Upper graph corresponds to tagged individuals, and lower graph to random
individuals. Numbers on top of the bars are indicating smaller than targeted samples due to deterioration of the sponge (tagged individuals, N ¼4 in year 1
and 10 in year 2), and bad weather or lack of sponges in the sampling area (random individuals, N ¼10).
Fig. 4. Percentage of individuals containing reproductive structures in relation to seawater temperature. Upper graph correspond to tagged individuals, and
bottom one to random individuals. N: none; O: oocytes; SC: spermatic cysts: TC: transdifferentiated choanocytes; SC +TC: males with both spermatic cysts
and transdifferentiated choanocytes; O +SC +TC: Hermaphrodites containing oocytes, spermatic cysts and transdifferentiated choanocytes. Number of
individuals collected (N) as in Figure 3.
reproduction in the sponge cliona delitrix 5
summer (Figures 3 &4). The transdifferentiated choanocytes
had a denser and larger nucleus (2–2.5 mm) than choanocytes
(11.5 mm), two or three large vacuoles, and some small mito-
chondria, all having lost the typical collar of choanocytes
(Figure 6G). Some other precursor cells had nuclei of similar
size or slightly larger (3 mm) than choanocytes showing syn-
aptonemal complexes, which are typical of prophase I in
primary spermatocytes (Figure 6H). A possible flagellum was
also observed in some of the primary spermatocytes
(Figure 6H). Transdifferentiation was synchronous within a
choanocyte chamber, with most of the choanocytes becoming
spermatogonia. Transdifferentiating choanocytes aggregated
and became surrounded by granulose cells, which also occurred
between them (Figure 6B, C). Aggregations of transdifferen-
tiated choanocytes were smaller than spermatic cysts (X+
SE ¼42.1 +14.6 mm, N ¼598).
Four different stages of development were identified in
spermatic cysts (Figure 6). At stage 1, cysts (X+SE ¼
61.8 +13 mm, N ¼15) contained mostly spermatogonia
(Figure 6C). Stage 2 cysts were larger than stage 1 cysts and
possibly contained spermatocytes I (X+SE ¼82.3 +
28.1 mm, N ¼69; Figure 6D). Stage 3 cysts (X+SE ¼
76.6 +26.7 mm, N ¼324) were almost the same average
size as stage 2 cysts and probably contained spermatids or
spermatozoa (Figure 6D E); they were difficult to discrimin-
ate from each other because we failed to observe them in TEM
samples and because a patent flagellum is already present in
both the spermatid and the spermatozoon of demosponges
(Riesgo et al.,2007; Riesgo & Maldonado, 2009). Stage 4
cysts were the largest stage observed (X+SE ¼109 +
34.1 mm, N ¼15), with the head of the spermatozoa accumu-
lated at one side of cyst and the flagella pointing in the oppos-
ite direction, likely ready for imminent spawning (Figure 6F).
Male individuals with mature spermatic cysts also simul-
taneously contained transdifferentiated choanocytes or
spermatic cysts in earlier maturation stages. This suggested
that spermatogenesis was also asynchronous at the individual
level, and designed to produce several pulses that appeared to
match the several oocyte cohorts noticed in the female indivi-
duals. In both years, about 10 43% of male individuals had
spermatic cysts simultaneously with transdifferentiated choa-
nocytes (Figure 4). Although at a population level transdiffer-
entiated choanocytes occured during all the reproductive cycle
(April December, Figure 4), at an individual level these cells
tended to disappear within a given individual after the appear-
ance of their spermatic cysts (Figure 7). The process of change
from transdifferentiated choanocytes to spermatic cyst 3 took
at least 5 days. Likewise, the development of cysts was not
necessarily a single continuous process within the individuals.
Some tagged individuals had two peaks during the annual
reproductive cycle (Figure 7), and transdifferentiation of
choanocytes appeared to last a month (Figure 7). These obser-
vations implied that transdifferentiated choanocytes were pro-
duced in pulses.
Assuming that spawning took place shortly after spermatic
cysts matured, it can be deduced that reproductive pulses
Fig. 5. Percentage of oocytes at different developmental stages for the tagged sponges that were females (N ¼4) in the sampling year 2010 2011. The other six
individuals: three were males (Figure 7) and three did not present any reproductive structure.
6 andia chaves-fonnegra et al.
occurred several times during summer, in consecutive months
and even twice in the same month (Figures 3 &4). In the first
year of study (2009 2010) ‘mature or nearly mature’ sperm-
atic cysts were observed at three different times (Figures 3 &
4), whereas during the second year (2010 2011) they were
observed five times (Figures 3 &4). Differences between
tagged and random individuals were observed; for example,
proportions of female and males were different, and the pres-
ence of spermatic cysts occurred only simultaneously in
tagged and random samples on 20 May 2010, 29 June 2011
and 20 July 2011 (Figure 3). These differences during repro-
ductive peaks, and that not all individuals engage in reproduc-
tion at each peak, clearly indicated that the whole population
was reproducing asynchronously (Figure 4). However, the
Fig. 6. Spermatogenesis observed by light microscopy and TEM. (A and B) Transdifferentiation of choanocytes into spermatogonia (Tc), in which choanocyte
chambers fuse with each other forming groups and interacting with granular cells. (C) Cyst stage 1 (with possible spermatogonia); (D) cyst stage 2 (spermatocytes I)
and cyst stage 3 (spermatids or spermatozoa) co-occurring in the same individual; (E) cyst stage 3 (spermatids or spermatozoa); (F) cyst stage 4 (condensed
spermatozoa). (G– H) TEM of transdifferentiated choanocytes. ch: choanocyte; f: flagellum; Gr: granulose cell; Pm: spermatozoa; s1: spermatocytes I; Scy:
spermatic cyst; sm: spermatids or spermatozoa; sn: synaptonemal complexes; Tc: transdifferentiated choanocytes.
reproduction in the sponge cliona delitrix 7
percentage of mature oocytes (stage IV) was higher (in three
of the eight reproductive events) when all observed spermatic
cysts were nearly mature (cyst 3) or mature (cyst 4) (Figure 8).
This correlation indicated that pulses of oogenesis and sperm-
atogenesis were coupled, with subpopulations of males and
females having the maturation of at least part of their
gametes synchronized for spawning and successful fertiliza-
tion. These synchronized spawning pulses occasionally
occurred twice a month, as was the case in August 2010 and
June 2011 (Figure 8). Although spermatic cysts were used to
indicate possible spawning events, coupled events with
mature female and male reproductive structures were fewer
(see Figure 8). This means that spermatic cysts and oocytes
in other events were not mature at the time of sampling, but
they were present and probably reached maturity later. It is
important to consider that we did not sample all the popula-
tion, and that other individuals not included in this study may
also be contributing to each spawning event.
Relation to environmental variables
Both percentage of individuals with reproductive structures and
density of reproductive structures were higher during the
warmer months of the year (Figures 3 &4). Mean density
(per sampling date) of reproductive structures increased with
increasing seawater temperature, although the strength of
such a statistical association was only moderate (oocytes:
Pearson r¼0.4, N¼41, P,0.05, including random and
tagged females both years, and Pearson r¼0.7, N¼12, P,
0.05, only including tagged females from second year;
transdifferentiated choanocytes: Spearman r¼0.7, N¼41, P
,0.05, including random and tagged males both years, and
Pearson r¼0.6, N¼12, P,0.05, only including tagged
males from second year). However, during the colder months
of the year, December to April for 2009–2010, and January
to March for 2010 2011, oocytes remained in stages I and II.
The winter of 2009 2010 was longer than that of the second
year, with a 1 month delay for water temperature to reach
the 258C threshold, and for oocytes to start stage III of develop-
ment (i.e. 258C was reached at the end of May in 2010 and
middle of April in 2011). Similarly, choanocytes started trans-
differentiation (to form spermatic cells) exactly at the same
time that oocytes started stage III of development. Thus,
water temperature above 258C appears to trigger the matur-
ation of oocyte cohorts (before and after winter) and it also sti-
mulates the transdifferentiation of choanocytes into
Based on the presence of spermatic cysts, three possible
spawning events were detected for 2010, and five for 2011.
All of them occurred during summer, 2 8 days before or
after full and new moons (Figure 9). Two spawning events a
month appeared to occur in August 2010, concurrent with
two full moons, and also in June 2001, but this time concur-
rent with a full and a new moons (June 2011). In August
2011 only spermatic cysts in early development were regis-
tered (cysts 1 and 2), suggesting two spawning events that
may possibly occur slightly later, probably during or after
August full and new moons (Figure 9). Spawning of gametes
was not fully synchronized with moon phases for all repro-
ductive events. However, three of the eight events in which
Fig. 7. Density of transdifferentiated choanocytes and spermatic cysts for the tagged sponges that were males (N ¼3) in year 2010– 2011. The other seven
individuals: four were females (Figure 5) and three did not present any reproductive structure.
8 andia chaves-fonnegra et al.
spermatic cysts were registered, occurred 3 4 days before the
full moon, and one more, 2 days before a new moon.
Considering the reproductive asynchrony characterizing C.
delitrix, it is possible that both full and new moons trigger
the spawning, and that only those individuals with gametes
near maturation at those given times participate in the
Sexuality and sex ratio
Most C. delitrix individuals were either male or females (gono-
choric), and sex reversal was never observed in the marked
individuals. Out of 650 individuals examined, only three
were corroborated to be simultaneous hermaphrodites: one
with spermatic cysts at stage 2, transdifferentiated choano-
cytes (early sperm cells), and oocytes at stage II as well; the
other two had both transdifferentiated choanocytes (early
sperm cells) and early oocytes (stage I). The weekly analysis
in August showed 2.9% of individuals were hermaphrodites
with oocytes and transdifferentiated choanocytes occurring
simultaneously. These data support that C. delitrix is essential-
ly a gonochoric species, but a small percentage of hermaphro-
ditic individuals occurs in the population (Figure 4). The
estimated sex ratio varied at each reproductive pulse, and
was closer to parity when both spermatic cysts and transdiffer-
entiated choanocytes were used to assign males (Table 2). It
departed from parity when only spermatic cysts were used
to assign males; in this case females were more frequent
during most reproductive peaks (Table 2).
Cliona delitrix is an oviparous, gonochoric sponge (rare herm-
aphrodite individuals can occur), with multiple spawning
events per year concentrated in the warmest months (water
temperature .258C). In this species the female gametogenesis
is longer than the male one, and asynchrony at the individual
and at the local population level occurs. However, synchro-
nized pulses of gametogenesis in male and female subpopula-
tions can happen for coupled spawning events. This study is
the first report of the reproductive cycle in C. delitrix and pre-
sents the first description of transdifferentiated choanocytes
into spermatic cells and the use of these cells to estimate fema-
le:male ratio and length of the reproductive period for the
genus Cliona.
Like other members of the genus Cliona, C. delitrix appears
to be oviparous (Piscitelli et al.,2011; Bautista-Guerrero et al.,
Fig. 8. Percentage of mature reproductive structures (only spermatic cysts 3 and 4 and oocytes stage IV) for summer 2010 (upper graph) and summer 2011 (lower
graph). Asynchrony at population level was evident, with subpopulations of females (oocytes) and males (spermatic cysts) matching for some spawning events (all
spawning events based only on the presence of spermatic cysts are shown in Figure 9). Spermatic cysts in August 2011 are not shown, as they were cysts in
stage 1 and 2.
reproduction in the sponge cliona delitrix 9
2014). Neither embryos nor larvae were observed in any indi-
vidual, suggesting that cleavage occurs once zygotes are
expelled from the sponges. Thus, embryogenesis seems to
occur outside the sponge, while fertilization could occur
either externally or internally. In the latter case, the zygotes
would be quickly expelled after fertilization for external devel-
opment, as reported for other clionaids (Maldonado & Riesgo,
2008; Bautista-Guerrero et al.,2014).
The presence of few hermaphroditic individuals in gono-
choric species such as Cliona delitrix is a common strategy
in sponges (e.g. Liaci & Sciscioli, 1967; Fell, 1970; Simpson,
1984; Baldacconi et al.,2007), and is due to genetic and
physiological factors, as well as to environmental cues
(Simpson, 1984; Ghiselin, 1987; McCartney, 1997; Prevedelli
et al.,2006). Hermaphroditism is also favoured in sessile
marine organisms, that unlike C. delitrix, are not very abun-
dant and display relaxed sperm competition and localized
gamete dispersal (McCartney, 1997). Having a low percentage
of simultaneous hermaphrodites may favour C. delitrix asyn-
chronous reproductive strategy, helping to equilibrate the
ratio of females:males during specific reproductive pulses.
The sex ratio in Cliona delitrix was variable and in most
cases departed from parity if only spermatic cysts were used
Fig. 9. Density (+SE) of spermatic cysts (all stages) in relation to moon phases for summer 2010 and 2011. Fraction of the moon illuminated is shown as
harmonic oscillation waves over time; full moon (peaks) and new moon (valleys). (): closest date to a spawning 2 August 2010: density of spermatic cysts
was higher, and only date in which cysts 4 were registered.
Table 2. Ratio of female to male individuals at each reproductive peak
combining tagged and randomly sampled individuals. Females and
males were assigned depending on the presence of only O: oocytes and
SC: spermatic cysts, and also for males adding both SC and Tc: transdif-
ferentiated choanocytes. Hermaphrodites were not included in the
Date (O: SC) (O: SC 1Tc)
(reproductive peak) Female :
Female :
20 May 2010 1:3 7 1:3 7
2 Aug 2010 1:1 8 1:1 8
20 Aug 2010 3:1 4 1:2 8
13 June 2011 5:1 11 3:1 12
29 June 2011 4:1 10 1:1 14
20 July 2011 1:2 15 1:2 15
10 Aug 2011 4:1 10 1:1 15
22 Aug 2011 4:1 18 1:1 26
Total 3:1 83 1:1 105
N: total number of individuals sampled; r: random individuals; t: tagged
10 andia chaves-fonnegra et al.
to assign males. In this case females were more frequent than
males, similar to C. vermifera (Bautista-Guerrero et al.,2014).
However, the sex ratio was closer to parity when transdiffer-
entiated choanocytes were also used to assign males. These
results suggest that parity may be the norm in this species,
and that reproduction in C. delitrix would agree with the
Du¨sing Fisher’s sex ratio principle (Queller, 2006).
Disparity in sex ratio as observed in other Cliona sponges
´lez-Rivero et al.,2013; Bautista-Guerrero et al.,2014)
may relate to sampling bias, as spermatogenesis is usually
very short, and the reproduction rhythm can be missed at
times. In this case, using transdifferentiated choanocytes can
help to trace male individuals for a couple of days more,
and match the reproduction rhythm in the population.
Cliona delitrix oocytes’ morphology and size were similar
compared with other Cliona spp. We found that oocytes inter-
acted with granular cells (nurse cells) from the beginning of
oogenesis. Previous reports of association of granular cells
and reproductive elements are restricted to mature oocytes
of some Cliona spp. and their larvae (Warburton, 1961;
Piscitelli et al.,2011). For males, granular cells were observed
interspersed and in continuous interaction with choanocytes
transdifferentiating into gametogonia. However granular
cells did not enter spermatic cysts at any time, implying that
they may only be involved in the process of transdifferentia-
tion of choanocytes into spermatic cells, but not in subsequent
stages. The development inside each spermatic cyst was syn-
chronous, as in C. vermifera (Bautista-Guerrero et al.,2014).
The length of the seasonal reproductive cycle of C. delitrix
overlaps with that of a few other sponges studied in Florida
(Maldonado & Young, 1996; Leong & Pawlik, 2011).
Considering that development of reproductive structures in
C. delitrix requires temperatures of 258C and above, we
hypothesize that in the tropics reproduction could occur
year around. In this case, the opportunity of colonizing new
coral colony substratum may be higher, as the sponges
would have more spawning events. However, food availability
and other environmental factors could limit its reproductive
potential (Maldonado & Riesgo, 2008). Additional studies of
sponges from tropical areas will be necessary to test this
Spawning of gametes was not synchronized with moon
phases. However, in four of eight reproductive events, sperm-
atic cysts were observed 24 days before the full or new
moons. Thus, it is possible that to a certain extent moon
phases triggered the development and spawning, permitting
two spawning events in the same month (i.e. June 2011).
The relationship between lunar phases and sponge spawning
has been suggested before for some species such as
Chondrilla australiensis Carter (1873), which spawns 11
days after the full moon (Usher et al.,2004), and
Neofibularia nolitangere Duchassaing & Michelotti (1864)
which starts releasing gametes on the third day after the full
moon (Hoppe & Reichert, 1987).
Although the C. delitrix reproductive cycle is seasonal, it
does not follow the typical pattern of seasonal oviparous
species of Cliona or Pione, which often have only one or
two highly synchronic major spawning events or zygote
releases during the warmest season (Pomponi & Meritt,
1990; Piscitelli et al.,2011; Bautista-Guerrero et al.,2014).
In contrast, C. delitrix reproduction has more than one repro-
ductive pulse, with possibly several spawning events per year,
similar to some viviparous sponges (e.g. Ilan & Loya, 1990;
Whalan et al.,2007). The percentage of reproductively
active C. delitrix individuals varies over time, gamete
development is asynchronous within the individuals, and pro-
duction of gametes occurred in discrete periods not synchro-
nized among all the individuals in the population. Therefore,
C. delitrix reproduction involves only a fraction of the popu-
lation at different times during the reproductive period, a
characteristic that places this species in the category of asyn-
chronous but year-round reproductive organisms (Gage &
Tyler, 1991; Witte, 1996; Mangubhai & Harrison, 2008).
Indeed, at the population level, oogenesis in C. delitrix
occurs as a continuous process over the year; even during
the coldest months early stage (I and II) oocytes were observed
in few individuals. Maintaining oocytes in the tissue after the
reproductive season is a characteristic that has not been
reported in other clionaids, as gametic activity typically
ceases after the release of eggs or zygotes (Piscitelli et al.,
2011; Bautista-Guerrero et al.,2014). This capability could
favour C. delitrix to engage in reproduction immediately
after the environmental conditions are suitable.
Cliona delitrix gamete status and reproductive cycle are
both different compared with reproductive cycles of Cliona
species from the Mediterranean (water temperature
15 328C), but similar to species in the Caribbean Sea and
the Pacific Ocean (22 328C). Mediterranean Sea C. celata
and C. viridis are hermaphrodites with longer oogenesis and
a very rapid spermatogenesis, which leads to one single
spawning event in May (Mariani et al.,2000; Piscitelli et al.,
2011). The Caribbean species C. delitrix and C. tenuis, and
the Pacific species C. vermifera are gonochoric
´lez-Rivero et al.,2013; Bautista-Guerrero et al.,
2014). Both C. delitrix and C. vermifera can have more than
two pulses of spermatogenesis and more than two cohorts
of oogenesis: C. delitrix between April and December and
C. vermifera between July and November (Bautista-Guerrero
et al.,2014). This scenario has also been suggested, but not
documented, for C. tenuis (Gonza
´lez-Rivero et al.,2013).
Multiple spawning events represent a strategy that increases
reproductive success by decreasing the risk of massive off-
spring mortality in the event of local adverse events
(Richmond & Hunter, 1990). In addition, it can increase the
chances of successful colonization, and the likelihood that
these species recruit at some point when suitable, unoccupied
substratum is available. The three species, C. delitrix, C. tenuis
and C. vermifera, colonize corals (Lo
´pez-Victoria & Zea, 2005;
Chaves-Fonnegra & Zea, 2011; Bautista-Guerrero et al.,2014),
and specifically C. delitrix has a preference for massive corals,
and recently dead coral where coral skeleton is clean and
exposed (Chaves-Fonnegra & Zea, 2011; Chaves-Fonnegra,
2014), whereas the Mediterranean species C. celata and
C. viridis colonize different types of calcareous substrata,
including limestone (Volz, 1939; de Groot, 1977; Mariani
et al.,2000). It is possible that having more reproductive
pulses can enhance changes of recruitment on a substratum
more difficult to find, such as recently dead coral skeletons
(Carballo et al.,2013; Chaves-Fonnegra, 2014).
The increase of coral bleaching and mortality (Hoegh-
Guldberg, 1999; Gardner et al.,2003; Eakin et al.,2010) pro-
vides more suitable substratum for coral-excavating sponges
to recruit (Scho
¨nberg & Ortiz, 2008; Carballo et al.,2013;
Chaves-Fonnegra, 2014). Therefore, multiple pulses of spawn-
ing events over the warmer months of the year are a strategy
that helps to guarantee recruitment and avoid competition for
reproduction in the sponge cliona delitrix 11
space (e.g. Whalan et al.,2007; Mangubhai & Harrison, 2008).
Indeed, as sponge spawning is occurring in the same season as
thermal stress and mortality in Caribbean corals (Eakin et al.,
2010), the possibility of C. delitrix larval recruitment on
exposed coral skeleton is even higher.
The number of spawning events detected appears to be
related to the intensity of sampling effort (number of individ-
ual collected, and number of times sampled). For example, in
2009 2010, sampling effort was less than in 2010 2011; as
result, the number of spawning events detected were three
in the first year, and five in the second. Considering that not
all the population reproduces simultaneously, increasing the
sampling effort during the reproductive cycle could show
more spawning per year for C. delitrix.
Overall, the versatile sexual reproduction of C. delitrix
appears to contribute to its proliferation. Its extended repro-
ductive cycle with multiple spawning events suggests that
C. delitrix has a reproductive strategy that reduces the risk
of massive offspring mortality during catastrophic events,
and it gives it a chance to compete for space with other reef
invertebrates (Richmond & Hunter, 1990; Mangubhai &
Harrison, 2008). Thus, the increase of C. delitrix on coral
reefs can be attributed not only to organic contamination by
sewage (Rose & Risk, 1985; Ward-Paige et al.,2005;
Chaves-Fonnegra et al.,2007), but also to its multi-spawning
reproductive strategy, that combined with its ability to kill
coral tissue and excavate coral skeletons much deeper
than most excavating sponges make of this species a suc-
cessful reef bioeroder (Pang, 1973; Chaves-Fonnegra & Zea,
2007,2011). In addition, climate change is increasing coral
mortality, and is opening more space for this sponge to
recruit on corals (Chaves-Fonnegra, 2014). Management
and coral restoration alternatives to control C. delitrix
should address the reduction of sewage waste, and factors
that are affecting coral health at a broad scale (i.e. CO
sions) (e.g. Hughes et al.,2003; Pandolfi et al.,2003). We rec-
ommend including C. delitrix in monitoring efforts around
the Caribbean Sea and Atlantic, as it is an important bioindi-
cator not only of water quality, but also of coral degradation
and bioerosion.
These results were presented by A.C.-F. as part of her PhD dis-
sertation in NOVA Southeastern University, Oceanographic
Center, Florida, USA. Fieldwork was possible thanks to the
NSU Diving Program, L. Robinson, D. Gilliam, K. O’Neil and
members of the NSU Coral Reef Restoration and Monitoring
Laboratory (CRRAM). Laboratory work was supported by
A. Renegar and members of the NSU Coral Histology and
Marine Microbiology and Genetics Laboratories. Special
thanks to S. Zea and B. Riegl for suggestions on methods and
analyses, and to S. Zea for C. delitrix photographs.
This work was funded through the UNESCO-L’Ore
´al Fellowship
for Young Women in Science, the PhD scholarship program
from Colombian Science and Technology Department
(COLCIENCIAS), Billfish Tournament Scholarship, the
Broward Women Association Scholarship, and the President’s
Faculty Research and Development Grant to JVL and AC-F by
Nova Southeastern University.
Baldacconi R., Nonnis-Marzano C., Gaino E. and Corriero G. (2007)
Sexual reproduction, larval development and release in Spongia
officinalis L. (Porifera, Demospongiae) from the Apulian coast.
Marine Biology 152, 969979.
Banks K.E., Riegl B.M., Richards V.P., Walker B.E., Helmle K.P. and
Jordan L.K.B. (2008) The reef tract of continental Southeast Florida
(Miami-Dade, Broward, and Palm Beach Counties, USA). In Riegl
B. and Dodge R.E. (eds) Coral reefs of the USA. New York, NY:
Springer-Verlag, pp. 175220.
Bautista-Guerrero E., Carballo J.L. and Maldonado M. (2014)
Abundance and reproductive patterns of the excavating sponge Cliona
vermifera: a threat to Pacific coral reefs? Coral Reefs 33, 259–266.
Carballo J.L., Bautista E., Nava H., Cruz-Barraza J.A. and Chavez J.A.
(2013) Boring sponges, an increasing threat for coral reefs affected by
bleaching events. Ecology and Evolution 3, 872886.
Carter H.J. (1873) On two new species of Gummineae, with special and
general observations. Annals and Magazine of Natural History 12,
1730, pl. I.
Chaves-Fonnegra A. (2014) Increase of excavating sponges on Caribbean
coral reefs: reproduction, dispersal and coral deterioration. Doctoral
dissertation. Nova Southeastern University, Dania Beach, 195 pp.
Chaves-Fonnegra A., Feldheim K.A., Secord J. and Lopez J.V. (2015)
Population structure and dispersal of the coral-excavating sponge
Cliona delitrix.Molecular Ecology 24, 14471466.
Chaves-Fonnegra A. and Zea S. (2007) Observations on reef coral under-
mining by the Caribbean excavating sponge Cliona delitrix
(Demospongiae, Hadromerida). In Custo
´dio M.R., Lo
ˆbo-Hajdu G.,
Hajdu E. and Muricy G. (eds) Porifera research: biodiversity, innov-
ation and sustainability. Rio de Janeiro: Museu Nacional, pp. 247 –254.
Chaves-Fonnegra A. and Zea S. (2011) Coral colonization by the encrust-
ing excavating Caribbean sponge Cliona delitrix.Marine Ecology 32,
162– 173.
Chaves-Fonnegra A., Zea S. and Go
´mez M.L. (2007) Abundance of the
excavating sponge Cliona delitrix in relation to sewage discharge at San
´s Island, SW Caribbean, Colombia. Boletı
´n de Investigaciones
Marinas y Costeras 36, 6378.
´s J., Murillo M., Guzma
´n H.M. and Acun
˜aJ.(1984) Pe
´rdida de
zooxantelas y muerte de corales y otros organismos arrecifales en el
Caribe y Pacı
´fico de Costa Rica. Revista de Biologı
´a Tropical 32,
227– 231.
de Groot R.A. (1977) Boring sponges (Clionidae) and their trace fossils
from the coast near Rovinj (Yugoslavia). Geologie en Mijnbouw 56,
168– 181.
Duchassaing De Fonbressin P. and Michelotti G. (1864) Spongiaires de
la mer Caraı
¨be. Natuurkundige verhandelingen van de Hollandsche
maatschappij der wetenschappen te Haarlem 21, 1 124, pls I XXV.
Duckworth A.R. and Peterson B.J. (2013) Effects of seawater tempera-
ture and pH on the boring rates of the sponge Cliona celata in
scallop shells. Marine Biology 160, 2735.
Eakin C.M., Morgan J.A., Heron S.F., et al.(2010) Caribbean corals in
crisis: record thermal stress, bleaching, and mortality in 2005. PLoS
ONE 5, 19.
Enochs I.C., Manzello D.P., Carton R.D., Graham D.M., Ruzicka R.
and Collela M.A. (2015) Ocean acidification enhances the bioerosion
of a common coral reef sponge: implications for the persistence of the
12 andia chaves-fonnegra et al.
Florida Reef Tract. Bulletin of Marine Science 91, doi: 10.5343/
bms.2014.1045 2015.
Fang J.H.K., Athayde M.A.M., Scho
¨nberg C.H.L., Kline D.I.,
Hoegh-Guldberg O. and Dove S. (2013) Sponge biomass and bioero-
sion rates under ocean warming and acidification. Global Change
Biology 19, 3581– 3591.
Fell P.E. (1970) The natural history of Haliclona ecbasis de Laubenfels, a
siliceous sponge of California. Pacific Science Journal 24, 381386.
Gage J.D. and Tyler P.A. (1991) Deep-sea biology: a natural history of
organisms at the deep sea floor. Cambridge: Cambridge University
Press, pp. 524.
Gardner T.A., I.M. C., Gill J.A., Grant A. and Watkinson A.R. (2003)
Long-term region-wide declines in Caribbean corals. Science 301,
958– 960.
Ghiselin M.T. (1987) Evolutionary aspects of marine invertebrate repro-
duction. In Giese C.A., Pearse J.S. and Pearse V.B. (eds) Reproduction
of marine invertebrates. Palo Alto, CA: Blackwell Scientific, pp. 609
Gilliam D.S. (2012) Southeast Florida coral reef evaluation and monitor-
ing project 2011. Year 9 Final Report. Florida DEP Report #RM085.
Miami Beach, FL. 49 pp.
´lez-Rivero M., Ereskovsky A.V., Scho
¨nberg C.H.L., Ferrari R.,
Fromont J. and Mumby P.J. (2013) Life-history traits of a common
Caribbean coral-excavating sponge, Cliona tenuis (Porifera:
Hadromerida). Journal of Natural History 47, 28152834.
Grant R.E. (1826) Notice of a new zoophyte (Cliona celata Gr.) from the
Firth of Forth. Edinburgh New Philosophical Journal 1, 7881.
Hancock A. (1849) On the excavating powers of certain sponges belong-
ing to the genus Cliona with descriptions of several new species, and an
allied generic form. Annals and Magazine of Natural History 3, 321
348, pls XIIXV.
Hancock A. (1867) Note on the excavating sponges; with descriptions of
four new species. Annals and Magazine of Natural History 19, 229
242, pls VIIVIII.
Hoegh-Guldberg O. (1999) Climate change, coral bleaching and the
future of the world’s coral reefs. Marine and Freshwater Research 50,
839– 866.
Holmes K.E. (1997) Eutrophication and its effect on bioeroding sponge
communities. In Lessios H.A. and Macintyre I.G. (eds) Proceedings
of the 8th International Coral Reef Symposium, Panama
´, 1997.
Smithsonian Tropical Research Institute, pp. 14111416.
Hoppe W.F. and Reichert M.J.M. (1987) Predictable annual mass release
of gametes by the coral reef sponge Neofibularia nolitangere (Porifera:
Demospongiae). Marine Biology 94, 277– 285.
Hughes T.P., Baird A.H., Bellwood D.R., Card M., Connolly S.R.,
Folke C., Grosberg R., Hoegh-Guldberg O., Jackson J.B.,
Kleypas J., Lough J.M., Marshall P., Nystro
¨m M., Palumbi S.R.,
Pandolfi J.M., Rosen B. and Roughgarden J. (2003) Climate
change, human impacts, and the resilience of coral reefs. Science
301, 929933.
Ilan M. and Loya Y. (1990) Sexual reproduction and settlement of the
coral reef sponge Chalinula sp. from the Red Sea. Marine Biology
105, 2531.
Lang J.C. (2003) Status of coral reefs in the Western Atlantic: results of
initial surveys, Atlantic and Gulf Rapid Reef Assessment (AGRRA)
Program. Atoll Research Bulletin 496, 1630.
Leong W. and Pawlik J.R. (2011) Comparison of reproductive patterns
among 7 Caribbean sponge species does not reveal a resource trade-off
with chemical defenses. Journal of Experimental Marine Biology and
Ecology 401, 8084.
´vi C. (1956) Etude des Halisarca de Roscoff. Embryologie et syste
tique des demosponges. Archives de Zoologie Expe
´rimentale et
´rale 93, 1–181.
Liaci L.S. and Sciscioli M. (1967) Osservazioni sulla maturazione sessuale
di un tetractinellide: Stelleta grubii O. S. (Porifera). Archivio Zoologico
Italiano 52, 169– 176.
´pez-Victoria M. and Zea S. (2005) Current trends of space occupation
by encrusting excavating sponges on Colombian coral reefs. Marine
Ecology, 26, 33– 41.
Maldonado M. (2009) Embryonic development of verongid demosponges
supports the independent acquisition of spongin skeletons as an alter-
native to the siliceous skeleton of sponges. Biological Journal of the
Linnean Society 97, 427447.
Maldonado M. and Bergquist P. (2002) Phylum Porifera. In Young C.
(ed.) Atlas of marine invertebrate larvae. Barcelona: Academic Press,
pp. 21– 50.
Maldonado M. and Riesgo A. (2008) Reproduction in the phylum
Porifera: a synoptic overview. In Durfort M. and Vidal F. (eds)
Biologia de la reproduccio
´, Volume 59. Barcelona: Societat Catalana
de Biologı
´a, pp. 29– 49.
Maldonado M. and Riesgo A. (2009) Gametogenesis, embryogenesis, and
larval features of the oviparous sponge Petrosia ficiformis
(Haplosclerida, Demospongiae). Marine Biology 156, 2181– 2197.
Maldonado M. and Young C. (1996) Effects of physical factors on larval
behavior, settlement and recruitment of four tropical demosponges.
Marine Ecology Progress Series 138, 169180.
Mangubhai S. and Harrison P.L. (2008) Asynchronous coral spawning
patterns on equatorial reefs in Kenya. Marine Ecology Progress Series
360, 8596.
Mariani S., Uriz M.J. and Turon X. (2000) Larval bloom of the oviparous
sponge Cliona viridis: coupling of larval abundance and adult distribu-
tion. Marine Biology 137, 783790.
McCartney M.A. (1997) Sex allocation and male fitness gain in a colonial,
hermaphroditic marine invertebrate. Evolution 51, 127– 140.
Miller A.W., Blackwelder P.L., Al-Sayegh H. and Richardson L.L.
(2011) Fine-structural analysis of black band disease-infected coral
reveals boring cyanobacteria and novel bacteria. Diseases of Aquatic
Organisms 93, 179– 190.
Nassonov N. (1883) Zur biologie und anatomie der Clione.Zeitschrift fu
Wissenschaftliche Zoologie 39, 295– 308.
Old M.C. (1941) The taxonomy and distribution of the boring sponges
(Clionidae) along the Atlantic coast of North America. Chesapeake
Biological Laboratory Publications 44, 130.
Pandolfi J.M., Bradbury R.H., Sala E., Hughes T.P., Bjorndal K.A.,
Cooke R.G., McArdle D., McClenachan L., Newman M.J., Paredes
G., Warner R.R. and Jackson J.B. (2003) Global trajectories of the
long-term decline of coral reef ecosystems. Science 301, 955 958.
Pang R.K. (1973) The systematics of some Jamaican excavating sponges
(Porifera). Postilla of the Peabody Museum of Natural History at
Yale University 161, 175.
Piscitelli M., Corriero G., Gaino E. and Uriz M.J. (2011) Reproductive
cycles of the sympatric excavating sponges Cliona celata and Cliona
viridis in the Mediterranean Sea. Invertebrate Biology 130, 1– 10.
Pomponi S.A. and Meritt D.W. (1990) Distribution and life history of the
boring sponge Cliona truitti in the Upper Chesapeake Bay. In Ru¨tzler
K. (ed.) New perspectives in sponge biology. Washington, DC:
Smithsonian Institution Press, pp. 384390.
Prevedelli D., Massamba n’siala G. and Simonini R. (2006)
Gonochorism vs. hermaphroditism: relationship between life history
and fitness in three species of Ophryotrocha (Polychaeta:
reproduction in the sponge cliona delitrix 13
Dorvilleidae) with different forms of sexuality. Journal of Animal
Ecology 75, 203212.
Queller D.C. (2006) Sex ratios and social evolution. Current Biology 16,
Renegar D.A., Blackwelder P.L., Miller J.D., Gochfeld D.J. and
Moulding A.L. (2008) Ultrastructural and histological analysis of
dark spot syndrome in Siderastrea siderea and Agaricia agaricites.In
Riegl B. (ed.) Proceedings of the 11th International Coral Reef
Symposium, Fort Lauderdale, pp. 185189.
Richmond R.H. and Hunter C.L. (1990) Reproduction and recruitment
of corals: comparisons among the Caribbean, the Tropical Pacific, and
the Red Sea. Marine Ecology Progress Series 60, 185203.
Riesgo A. and Maldonado M. (2009) An unexpectedly sophisticated,
V-shaped spermatozoon in Demospongiae (Porifera): reproductive
and evolutionary implications. Biological Journal of the Linnean
Society 97, 413– 426.
Riesgo A., Maldonado M. and Durfort M. (2007) Dynamics of gameto-
genesis, embryogenesis, and larval release in a Mediterranean homo-
sclerophorid demosponge. Marine and Freshwater Research 58,
398– 417.
Rose C.S. and Risk M.J. (1985) Increase in Cliona delitrix infestation of
Montastraea cavernosa heads on an organically polluted portion of
the Grand Cayman. Pubblicazioni della Stazione Zoologica di Napoli
Marine Ecology 6, 345363.
¨tzler K. (2002) Impact of crustose clionid sponges on Caribbean reef
corals. Acta Geologica Hispa
´nica 37, 6172.
Schmidt O. (1862) Die Spongien des Adriatischen Meeres. Leipzig:
Wilhelm Engelmann.
¨nberg C.H.L. (2001) Small-scale distribution of Australian bioerod-
ing sponges in shallow water. Ophelia 55, 39 54.
¨nberg C.H.L. and Ortiz J.-C. (2008) Is sponge bioerosion increas-
ing? Proceedings of the 11th International Coral Reef Symposium,
Fort Lauderdale, USA. pp. 520523.
Simpson T.L. (1984) The cell biology of sponges. New York, NY:
Springer-Verlag, pp. 662.
Topsent E. (1900) Etude monographique des spongiaires de France: III.
Monaxonides Hadromerina. Archives de Zoologie Expe
´rimentale et
´rale 8, 1– 331.
Usher K., Sutton D., Toze S., Kuo S. and Fromont J. (2004) Sexual
reproduction in Chondrilla australiensis (Porifera: Demospongia).
Marine and Freshwater Research 55, 123 134.
Volz P. (1939) Die Bohrschwa
¨mme (Clioniden) der Adria. Thalassia 3,
Warburton F.E. (1961) Inclusion of parental somatic cells in sponge
larvae. Nature 191, 1317.
Ward-Paige C.A., Risk M.J., Sherwood O.A. and Jaap W.C. (2005)
Clionid sponge surveys on the Florida Reef Tract suggest land-based
nutrient inputs. Marine Pollution Bulletin 51, 570579.
Weil E. (2002) Sponge-induced coral mortality in the Caribbean. A poten-
tial new threat to Caribbean coral reefs. In Sara
`M., Arillo A. and della
Croce N. (eds) Proceedings of the VI Internacional Sponge Conference,
Genova,. Canessa, pp. 211212.
Whalan S., Battershill C. and Nys R.d. (2007) Sexual reproduction of the
brooding sponge Rhopaloeides odorabile.Coral Reefs 26, 655– 663.
Wisshak M., Scho
¨nberg C.H.L., Form A. and Freiwald A. (2012) Ocean
acidification accelerates reef bioerosion. PLoS ONE 7, 18.
Wisshak M., Scho
¨nberg C.H.L., Form A. and Freiwald A. (2014) Sponge
bioerosion accelerated by ocean acidification across species and lati-
tudes? Helgoland Marine Research 68, 253262.
Witte U. (1996) Seasonal reproduction in deep-sea sponges triggered by
vertical particle flux? Marine Biology 124, 571581.
Zea S. and Weil E. (2003) Taxonomy of the Caribbean excavating sponge
species complex Cliona caribbaea C. aprica C. langae (Porifera,
Hadromerida, Clionaidae). Caribbean Journal of Science 39, 348– 370.
Zilberberg C., Maldonado M. and Sole
´-Cava A.M. (2006) Assessment of
the relative contribution of asexual propagation in a population of the
coral-excavating sponge Cliona delitrix from the Bahamas. Coral Reefs
25, 297– 301.
Correspondence should be addressed to:
A. Chaves-Fonnegra
NOVA Southeastern University, Oceanographic Center, 8000
North Ocean Drive. Dania Beach, FL, 33004, USA
14 andia chaves-fonnegra et al.
... Extended reproductive seasons have been described from Kenyan reefs 72 and on Lizard Island, Great Barrier Reef, where the spawning season of Acropora assemblages can last five months or more 72,87 . Additionally, both a fungiid coral from the Galápagos 88 and a Caribbean reef sponge 89 were also reported to have extended periods of reproductive activity and spawning of gametes that were not reliably adjusted to the lunar cycle. Unlike M. flabellata, however, they are both gonochoric, and fertilization for the sponge specifically could be external or internal 89 , an option not available for hermaphroditic broadcasting corals. ...
... Additionally, both a fungiid coral from the Galápagos 88 and a Caribbean reef sponge 89 were also reported to have extended periods of reproductive activity and spawning of gametes that were not reliably adjusted to the lunar cycle. Unlike M. flabellata, however, they are both gonochoric, and fertilization for the sponge specifically could be external or internal 89 , an option not available for hermaphroditic broadcasting corals. Chamberland, et al. 90 reported the Caribbean broadcasting coral Diploria labyrinthiformis to spawn for six consecutive months, but that species still had an identifiable, narrow four-day spawning window 10-13 days after the full moon each month. ...
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Sessile invertebrates often engage in synchronized spawning events to increase likelihood of fertilization. Although coral reefs are well studied, the reproductive behavior of most species and the relative influence of various environmental cues that drive reproduction are not well understood. We conducted a comparative examination of the reproduction of the well-studied Hawaiian coral Montipora capitata and the relatively unknown reproduction of its congener, Montipora flabellata. Both are simultaneous hermaphroditic broadcast spawners that release egg-sperm bundles with external fertilization. Montipora capitata had a distinct reproductive pattern that resulted in coordinated gamete maturation and the synchronized release of thousands of egg-sperm bundles across two spawning pulses tightly coupled to consecutive new moon phases in June and July. Montipora flabellata exhibited a four month reproductive season with spawning that was four-fold less synchronous than M. capitata; its spawning was aperiodic with little linkage to moon phase, a broadly distributed release of only dozens or hundreds of bundles over multiple nights, and a spawning period that ranged from late June through September. The reproductive strategy of M. flabellata might prove detrimental under climate change if increased frequency and severity of bleaching events leave it sparsely populated and local stressors continue to degrade its habitat.
... As expected, it has been observed that the number of spermatic cysts is higher than the female reproductive elements in D. janiae, probably because the former is the single element that has to leave the parental-sponge to find the eggs. Hence, the large number of sperm released in the water column increases the chance of reproduction being successful (Chaves-Fonnegra et al. 2015). At least 24% of the observed spermatic cysts had asynchronously developed cells, presenting at the same time two stages: either spermatogonia and spermatocyte or spermatocyte and spermatids/spermatozoa. ...
... Asynchrony in the maturation of different spermatic cysts in the same individual is not an uncommon characteristic in demosponges (e.g. Kaye and Reiswig 1991a;Chaves-Fonnegra et al. 2015;Vasconcellos et al. 2019). However, non-synchronisation within the same cyst is rare in Dictyoceratida, being more common in sponges of the class Homoscleromorpha, freshwater demosponges and members of the family Astrophorida (Demospongiae) (Fell 1974;Spetland et al. 2007;Ereskovsky 2010). ...
In the tropics, the marine sponge Dysidea janiae lives in obligatory symbiosis with the red macroalga Jania adhaerens. However, how this symbiosis is achieved, and how it influences the reproduction of the sponge is still unknown. We analysed the influence of environmental variables on the gametogenesis and embryogenesis of the sponge. We also investigated the histology of the reproductive propagules of the sponge over 3 years, aiming to understand how this symbiosis is established. Dysidea janiae is viviparous and gonochoristic, with a continuous but small reproductive effort. The reproductive dynamics of gametes and embryos were explained by different sets of environmental variables. Although the temperature was not directly related to the reproduction of the sponge in general, there was an increase in the density of spermatic cysts during the year when the El Niño occurred. The day length was related to the embryo dynamics, which were interpreted as an indirect effect of the increase in photosynthetic rates of the symbiont on the energetic budget of the sponge. As no algal propagules were found associated with the eggs or larvae of the sponge, the acquisition of the algae by the sponge is probably a ‘trial-and-error’ relationship after larval release. We propose that the symbiosis increases the fitness of the adult sponge, forcing the larvae to seek new macroalgae to settle on and start a new symbiosis all over again.
... This is mainly attributed to overexploitation, pollution, and parasites [9][10][11][12]. Gametogenesis is the process in which gametocytes undergo cell division and differentiation to form haploid gametes [13]. The sex ratio is a fundamental indicator for reproduction success in dioecious species, in which, nearly equal numbers of males and females are produced, giving a balanced sex ratio, whereas the sex ratio can skew towards one sex in hermaphroditic species [14,15]. ...
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Background Paphia undulata, The Short-Necked Clam, is an edible marine bivalve that is consumed internationally and locally in Egypt. Overfishing and pollution have caused population declines in Egyptian fisheries during the last decade. Accurate reproductive biology knowledge is critical for designing long-term exploitation strategy for this resource. P. undulata spawning and gametogenic cycle research were carried out from January to December 2020 along Timsah Lake, Suez Canal, Egypt. Results These clams are functionally dioecious with a very low incidence of hermaphroditism. The sex ratio of the clam population was 1.0:1.07:0.04 for male, female and hermaphrodite respectively. The shell lengths of the collected clams were 4.64 ± 0.83 cm in males, 4.55 ± 0.9 cm in females and 4.19 ± 0.3 cm in hermaphrodite clams. The sizes at the onset of sexual maturity in both males and females were 2.1 cm and 2.5 cm respectively. Conclusions Reproductive studies revealed that this species has a prolonged spawning season that is not restricted to a specific period.
... The reproduction biology of Cliona has been studied extensively for several species, including Cliothosa delitrix 93 , C. tenuis 92 , C. vermifera 94 , C. celata and C. viridis 95 . In these studies, C. vermifera and C. tenuis were determined to be gonochoric, C. celata and C. viridis hermaphoroditic, and Cliothosa delitrix mostly gonochoric with some hermaphrodites observed. ...
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Discovered in 1819 in the tropical waters off Singapore, the magnificent Neptune’s cup sponge Cliona patera (Hardwicke, 1820) was harvested for museums and collectors until it was presumed extinct worldwide for over a century since 1907. Recently in 2011, seven living individuals were rediscovered in Singapore with six relocated to a marine protected area in an effort to better monitor and protect the population, as well as to enhance external fertilisation success. To determine genetic diversity within the population, we sequenced the complete mitochondrial genomes and nuclear ribosomal DNA of these six individuals and found extremely limited variability in their genes. The low genetic diversity of this rediscovered population is confirmed by comparisons with close relatives of C. patera and could compromise the population’s ability to recover from environmental and anthropogenic pressures associated with the highly urbanised coastlines of Singapore. This lack of resilience is compounded by severe predation which has been shrinking sponge sizes by up to 5.6% every month. Recovery of this highly endangered population may require ex situ approaches and crossbreeding with other populations, which are also rare.
... This is also true for the sea anemone Nematostella vectensis, which may spawn weekly when provided the proper dietary conditions and photoperiodtemperature combination [195,196]. Similarly, sponges from a number of genera exhibit predictable and synchronous reproductive events in response to an increase in temperature and a lengthening of the photoperiod (e.g., [76,[197][198][199]). This reliability has yet to translate to the laboratory. ...
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Marine sponges (phylum Porifera) form symbioses with diverse microbial communities that can be transmitted between generations through their developmental stages. Here, we integrate embryology and microbiology to review how symbiotic microorganisms are transmitted in this early-diverging lineage. We describe that vertical transmission is widespread but not universal, that microbes are vertically transmitted during a select developmental window, and that properties of the developmental microbiome depends on whether a species is a high or low microbial abundance sponge. Reproduction, development, and symbiosis are thus deeply rooted, but why these partnerships form remains the central and elusive tenet of these developmental symbioses.
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Background The Short-Necked Clam Paphia undulata is a marine edible bivalve consumed all over the world and locally in Egypt. In the past decade, its population declined across the Egyptian fisheries due to overexploitation and pollution. The gametogenic cycle and spawning studies of P. undulata were carried out during the period from January 2020 to December 2020 along Timsah Lake, Suez Canal, Egypt. Results Shell lengths of the collected clams ranged from 2.31 cm to 6.22 cm in males, 2.05 cm to 5.97 cm in females and 3.70 cm to 4.36 cm in hermaphrodite clams. These clams are functionally dioecious wherein male and female sexes are separate, with very low incidences of hermaphroditism. The sex ratio (male: female: hermaphrodite) of the clam population was 1.0: 1.07: 0.04. The onset of sexual maturity of both males and females was 2.3 cm and 2.7 cm respectively. Conclusions Reproductive studies revealed that this species has a prolonged spawning season not restricted during a certain period.
Full-text available
The Short-Necked Clam Paphia undulata is a marine edible bivalve consumed all over the world and locally in Egypt. In the past decade, its population declined across the Egyptian fisheries due to overexploitation and pollution. The gametogenic cycle and spawning studies of P. undulata were carried out during the period from January 2020 to December 2020 along Timsah Lake, Suez Canal, Egypt. Shell lengths of the collected clams ranged from 2.31 cm to 6.22 cm in males, 2.05 cm to 5.97 cm in females and 3.70 cm to 4.36 cm in hermaphrodite clams. These clams are functionally dioecious wherein male and female sexes are separate, with very low incidences of hermaphroditism. The sex ratio (male: female: hermaphrodite) of the clam population was 1.0: 1.07: 0.04. The onset of sexual maturity of both males and females was 2.3 cm and 2.7 cm respectively. Reproductive studies revealed that this species has a prolonged spawning season not restricted during a certain period.
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Along the east Florida coast, 602 species of invertebrates have been identified on nearshore reefs. Ecological functions of invertebrates in this area include those organisms that: (1) increase local diversity of fishes and invertebrates via enhancing shelter availability, and/or (2) serve as predators or prey in local food webs. Generally, the highest community biomasses occur in reef areas with higher abundances of foundation invertebrate species that enhance local shelter and reduce environmental stress. A major example is the reef-building polychaete, Phragmatopoma lapidosa (caudata), which can be abundant along the central sections of the Florida coast and creates important structure that supports high diversities of invertebrates and fishes. In some areas, hard and soft corals, sponges, tunicates, mollusks, and barnacles function similarly. In contrast, many invertebrates also function as predators, prey, or both. In this capacity, they can be important in local food webs. Taxonomic groups that serve this function are sponges, crabs, polychaetes, echinoderms, and shrimp. Both functions likely vary dramatically with depth and latitude along the east Florida coast. Additional research is needed to better understand such spatial variability as well the dispersal and connectivity of important foundation species along the coast.
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Temporal patterns in giant barrel sponge (Xestospongia muta) spawning were compiled from 32 observations spanning 17 years and three Caribbean locations (Florida, Belize, and Haiti). The records were analyzed for patterns in seasonality, lunar periodicity, and diel rhythm to develop a predictive spawning window. Results indicate that spawning is concentrated from mid-April to late May. Most spawning events occurred around the first quarter moon; a smaller pulse occurred just before the third quarter moon. All spawning events were observed in the morning and fell within 779–987 min of the previous night’s sunset. Eggs of X. muta were all negatively buoyant and blanketed the areas within and surrounding the sponge; this limited gamete dispersal may be the driver behind heavily localized genetic retention.
Sponges are a major component of benthic ecosystems across the world and fulfil a number of important functional roles. However, despite their importance, there have been few attempts to compare sponge assemblage structure and ecological functions across large spatial scales. In this review, we examine commonalities and differences between shallow water (<100 m) sponges at bioregional (15 bioregions) and macroregional (tropical, Mediterranean, temperate, and polar) scales, to provide a more comprehensive understanding of sponge ecology. Patterns of sponge abundance (based on density and area occupied) were highly variable, with an average benthic cover between ~1 and 30%. Sponges were generally found to occupy more space (percentage cover) in the Mediterranean and polar macroregions, compared to temperate and tropical macroregions, although sponge densities (sponges m–2) were highest in temperate bioregions. Mean species richness standardised by sampling area was similar across all bioregions, except for a few locations that supported very high small‐scale biodiversity concentrations. Encrusting growth forms were generally the dominant sponge morphology, with the exception of the Tropical West Atlantic, where upright forms dominated. Annelids and Arthropods were the most commonly reported macrofauna associated with sponges across bioregions. With respect to reproduction, there were no patterns in gametic development (hermaphroditism versus gonochorism), although temperate, tropical, and polar macroregions had an increasingly higher percentage of viviparous species, respectively, with viviparity being the sole gamete development mechanism reported for polar sponges to date. Seasonal reproductive timing was the most common in all bioregions, but continuous timing was more common in the Mediterranean and tropical bioregions compared to polar and temperate bioregions. We found little variation across bioregions in larval size, and the dominant larval type across the globe was parenchymella. No pattens among bioregions were found in the limited information available for standardised respiration and pumping rates. Many organisms were found to predate sponges, with the abundance of sponge predators being higher in tropical systems. While there is some evidence to support a higher overall proportion of phototrophic species in the Tropical Austalian bioregion compared to the Western Atlantic, both also have large numbers of heterotrophic species. Sponges are important spatial competitors across all bioregions, most commonly being reported to interact with anthozoans and algae. Even though the available information was limited for many bioregions, our analyses demonstrate some differences in sponge traits and functions among bioregions, and among macroregions. However, we also identified similarities in sponge assemblage structure and function at global scales, likely reflecting a combination of regional‐ and local‐scale biological and physical processes affecting sponge assemblages, along with common ancestry. Finally, we used our analyses to highlight geographic bias in past sponge research, and identify gaps in our understanding of sponge ecology globally. By so doing, we identified key areas for future research on sponge ecology. We hope that our study will help sponge researchers to consider bioregion‐specific features of sponge assemblages and key sponge‐mediated ecological processes from a global perspective.
Deep-Sea Biology provides a comprehensive account of the natural history of the organisms associated with the deep-sea floor, and examines their relationship with this remote and inhospitable environment. In the initial chapters, the authors describe the physico-chemical nature of the deep-sea floor and the methods used to collect and study its fauna. They then go on to discuss the ecological framework by exploring spatial patterns of diversity, biomass, vertical zonation and large-scale distributions. Subsequent chapters review current knowledge of feeding, respiration, reproduction and growth processes in these communities. The unique fauna of hydrothermal vents and seeps are considered separately. Finally, there is a discussion of man's exploitation of deep-sea resources and his use of this environment for waste disposal on the fauna of this, the earth's largest ecosystem.
While simultaneous hermaphroditism occurs in most animal phyla, theories for its adaptive significance remain untested. Sex allocation theory predicts that combined sexes are favored in sedentary and sessile organisms because localized gamete dispersal and local mate competition (LMC) among gametes promote decelerating fitness "gain curves" that relate male investment to reproductive success. Under this LMC model, males fertilize all locally available eggs at low sperm output, additional output leads to proportionally fewer fertilizations, and combined sexes with female-biased sex allocation are favored. Decelerating male gain curves have been found in hermaphroditic flowering plants, but the present paper reports the first analysis in an animal. The colonial hermaphroditic bryozoan Celleporella hyalina forms unisexual male and female zooids that can be counted to estimate absolute and relative gender allocations. I placed "sperm donor" colonies-each with different numbers of male zooids, and each homozygous for diagnostic allozyme alleles-among target maternal colonies on field mating arrays, and estimated donor fertilization success by scoring allozyme markers in target-colony progeny. Fertilization success increased with numbers of donor male zooids, but linear and not decelerating curves fit the data best. Mean sex allocation was not female biased, consistent with nondecelerating male gain. Sperm donors, moreover, did not monopolize matings as expected under high LMC, but rather shared paternity with rival colonies. Hence localized water-borne gamete dispersal alone may not yield decelerating male gain and favor the maintenance of hermaphroditism; relaxed sperm competition in low density populations might also be required. In free-spawning marine organisms, males cannot control access to fertilizations, intense sperm competition may be commonplace, and high male sex allocation may be selected to enhance siring success under competition.